52 GERMINAL SELECTION. 



on personal selection. Were this so, a complete scale 

 of the most varied shades of color must have been 

 continually presented as variations in every species, 

 which certainly is not the case. For example, when 

 the exempt species Acrcsa Egina, whose coloration is 

 a brick-red, a color common only in the genus Acraea, 

 is mimicked by two other butterflies, a Papilio and a 

 Pseudacrsea, so deceptively that not only the cut of 

 the wings and the pattern of their markings, but also 

 that precise shade of brick-red, which is scarcely ever 

 met with in diurnal butterflies, are produced, assuredly 

 such a result cannot rest on accidental, but must be 

 the outcome of a definitely directed, variation, pro- 

 duced by utility. We cannot assume that such a col- 

 oration has appeared as an accidental variation in just 

 and in only these two species, which fly together with 

 the AcrcEa in the same localities of the same country 

 and same part of the world — ^the Gold Coast of Africa. 

 It is conceivable, indeed, that non-directed variation 

 should have accidentally produced this brick-red in 

 a single case, but that it should have done so three 

 times and 'in three species, which live together but 

 are otherwise not related, is a far more violent and 

 improbable assumption than that of a causal connexion 

 of this coincidence. Now hundreds of cases of such 

 mimicry exist in which the color-tints of the copy are 

 met with again in more or less precise and sometimes 

 in exceedingly exact imitations, and there are thou- 

 sands of cases in which the color-tint of a bark, of 

 a definite leaf, of a definite blossom, is repeated exactly 

 in the protectively colored insect. In such cases there 

 can be no question of accident, but the variations pre- 

 sented to personal selection must themselves have 

 been produced by the principle of the survival of the 



